src/mac.h

   1 /*
   2 */
   3
   4 #ifndef _HAVE_MAC_H
   5 #define _HAVE_MAC_H
   6
   7 #define MAXLINE 1024
   8 #define MAC_HASHSIZE 19963 //28001 //19963 //18899
   9
  10 /* GRR... on 64 bits there is no problem. on 32 bits, not so...
  11  * #define MAC_HASH(mac) (( (((uint32_t)mac[0]) ^ ((uint32_t)mac[1]) << 24) ^ ( ((uint32_t)mac[2]) << 16) ^ (mac[3]<<8) ^ (mac[4] ^ mac[5]) ) % MAC_HASHSIZE)
  12
  13  * we need a monotonic rising hash for lookups to be just right.
  14  * otherwise, we can't search "near" the hash for a match.
  15  */
  16 static inline uint32_t hash_mac(const uint8_t mac[], const uint8_t octets)
  17 {
  18    int i;
  19    uint32_t hash = 0;
  20    for(i = 0; i < octets; i++){
  21       //hash ^= mac[i] << ( (i*8) % 24); // reverse
  22       hash ^= mac[i] << (24 - ((i*8) % 24) );
  23    }
  24    //printf("hash is %d\n", hash %MAC_HASHSIZE);
  25    return hash % MAC_HASHSIZE;
  26 }
  27
  28 #define SKIP_SPACES(s) do { while(isspace(*s)) s++; } while (0)
  29
  30 int load_mac(const char *file, mac_entry **sigp[], int hashsize);
  31 mac_entry *match_mac(mac_entry **db, const uint8_t mac[], uint8_t mask);
  32 void print_mac(const uint8_t *mac);
  33 void dump_macs(mac_entry **db, int len);
  34 #endif /* ! _HAVE_MAC_H */